Biomedical subjects

T Hieda

Publications and source records attributed to T Hieda.

At least 37 records · Page 2Linked to original sources

PubMed1989

[A case of Prader-Willi syndrome].

Prader-Willi syndrome is characterized by hypotonia, hypomentia, hypogonadism and obesity. A case of a 10-year-5-month-old girl who was diagnosed to have the typical symptoms associated with the Prader-Willi syndrome is described in the present report. The following are the dental findings. 1) Enamel hypoplasia, crowding over the anterior teeth and narrow dental arch were found. However there was no high palate in the maxilla. 2) The mesio-distal width of the present teeth were small compared with the national average. 3) According to X-ray cephalometric analysis, a retardation of the growth of the maxilla and mandible was found. 4) Because of hypomentia and the difficult management of the patient, dental treatment was performed under general anesthesia.

Cephalometry↗

PubMed1989

[Study of pit and fissure sealants. The effect of viscosity of the sealants and type of the applicators on the administration time and the sealed area].

From the standpoint of the durability of the sealants, it is assumed that the sealants should be applied only to the bottom part of the pit and fissure to avoid marginal fracture and wear of the materials. Because of this, a minimum area for the sealant to be applied is required for a stable prevention of dental caries. The purpose of this study was to investigate the effect of viscosity of the sealants and various applicators in the techniques for minimum-area-sealing. Three sealants with various degrees of viscosity were applied to the stone models of a lower first molar by means of four types of applicators. Three operators conducting the experiment were a dentist with two years of experience, a dentist with one year of experience and a student. The time required for administration and the area of sealed pits and fissures were evaluated. The following results were obtained. 1. The sealants with a lower degree of viscosity revealed a shorter administration time and a narrower sealed area. 2. The applicators with thinner nozzles brought about a shorter administration time and a narrower sealed area. 3. The administration time did not exhibit significant differences among the operators, while the sealed area exhibited significant differences. 4. The longer the period of the clinical experience of the operator, the narrower the sealed area obtained. From the above results, it is recommended to select a sealant with low viscosity and utilize an applicator with a thin nozzle or a brush with a fine tip to obtain the minimum-sealing-area. Additionally, prior to the clinical trial, one should become acquainted with the characteristics of the sealant as well as the manipulation of the applicator.

Pit and Fissure Sealants↗

PubMed1989

[Traumatic injuries to the teeth for children].

For modern medical care, social background may be an essential factor, and medical care through out the individual's life time appears to have significant meaning. From this point of view, total dental care throughout childhood is being carried out in the field of pediatric dentistry. It can be stated that we pedodontists have a degree of farsight in the treatment of traumatic injuries to the teeth regarding children (the theme of the lecture), since the injured teeth are treated not only as items to be restored but also as a part of the growing body with careful consideration on the effects with regard to orlo-facial growth. It is obvious that epidemiological surveilance is necessary to understand the cause of dental injuries, and also careful attention ought to be paid to the activity of the children to grasp the potential background of dental trauma. Here, I would like to explain the consequences of the serial work on the traumatic injuries to teeth which were carried out in our department. 1) The prevalence of dental injuries in children appeares to be on the increase according to a judgement based on the surveilances form in and out of the country. Also as the parental recognition for dental injuries became higher, more patients visited dental clinic or hospital looking for improved treatment techniques. 2) Careful consideration must be paid to the succedaneus permanent tooth germ, when a deciduous tooth suffered from traumatic injury. The effect of the direction applied and the area of the traumatic force on the root of the deciduous tooth, the successor and the surrounding tissue was investigated by means of kinetic analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗

PubMed1989

Calcification of the permanent first molars observed in panoramic radiographs.

We investigated the development (calcification) stages of the permanent first molars of Japanese children by classifying them into 14 stages by the criterion of Moorrees, et al., using 11,167 panoramic radiographs, 5,759 of boys and 5,408 of girls, between the ages of 2 years 0 months and 14 years 11 months. The following information was obtained from calculations of the average chronological ages for the development stages of these teeth. 1) The development of first molars was earlier in girls than boys. This was particularly true during the middle phase of development. 2) A first molar on one side developed at the same rate as its counterpart on the other side, regardless of differences in sex or arch. 3) In both boys and girls, the development of the mandibular first molars was about one month earlier than that of the maxillary first molars at each stage. 4) When these results were compared with those of Nolla, Moorrees and Haavikko, who pioneered this field of study, it was clear that the development of the teeth in Japanese is different from that in Caucasians. 5) We made charts of the development of the first molars in Japanese which can be applied in routine clinical practice.

Adolescent↗

PubMed1989

Morphological characteristics of the teeth of Newar children.

The morphology of the teeth of Newar children was investigated in order to determine racial characteristics of the teeth in comparison with those of Japanese. The results were as follows. 1) The incidence of a C type labial surface pattern on the maxillary incisors was greater in Newars than Japanese for both the maxillary central and lateral incisors. 2) The total incidence of shovel-shaped and semi-shovel-shaped maxillary incisors was greater than 80% in Japanese, although at most about 25% in Newars. 3) The incidence of interstitial tubercles on the maxillary premolars in Newars was less than in Japanese. 4) The incidence of the cusp of Carabelli on maxillary first molars was greater in Newars than in Japanese. 5) Although the incidence of protostylids on the mandibular first molars was less in Newars than in Japanese, the incidence of the + type occlusal groove pattern was higher in Newars. Even though four-cusp mandibular first molars were more common in Newars than in Japanese, the incidence of a sixth cusp was lower in Newars. Also, the incidence of a sixth cusp was lower in Newars. Also, the incidence of medial of medial lingual accessory tubercles was slightly higher in Newars than in Japanese. Examination of the Newar teeth confirmed previous findings that they are racially Caucasoid, although they have some similarities with Japanese.

Dentition↗

PubMed1988

Microbial Conversion of alpha-Ionone, alpha-Methylionone, and alpha-Isomethylionone.

alpha-Ionone, alpha-methylionone, and alpha-isomethylionone were converted by Aspergillus niger JTS 191. The individual bioconversion products from alpha-ionone were isolated and identified by spectrometry and organic synthesis. The major products were cis-3-hydroxy-alpha-ionone, trans-3-hydroxy-alpha-ionone, and 3-oxo-alpha-ionone. 2,3-Dehydro-alpha-ionone, 3,4-dehydro-beta-ionone, and 1-(6,6-dimethyl-2-methylene-3-cyclohexenyl)-buten-3-one were also identified. Analogous bioconversion products from alpha-methylionone and alpha-isomethylionone were also identified. From results of gas-liquid chromatographic analysis during the fermentation, we propose a metabolic pathway for alpha-ionones and elucidation of stereochemical features of the bioconversion.

Journal Article↗

PubMed1988